Chapter 7- Life History

LT 1: Life history traits represent the schedule of an organism’s life

Life History- the schedule of an organism’s growth, development, reproduction and, survival

Fecundity- the number of offspring produced by an organism per reproductive episode

Parity- the number of reproductive eposides that an organism experiences

Parental Investment- the amount of time and energy given to an offspring by its parents

Longevity- the life span of an organism

LT 2: Life history traits are shaped by trade-offs

Princliple of allocation- the observation that when resources are devoted to one body structure, physiological function, or behavior they cannopt be allotted to another.

Determinate growth- a growth pattern in which an individual does not grow any more once it initiates reproduction

Indeterminate growth- a growth pattern in which an individual continues to grow after initiating reproduction

LT3 : Organisms differ in the number of times they reproduce, but they all become senescent (grow old)

Semalparity- when organisms reproduce only one during their life

Iteroparity- when organisms reproduce multiple times during their life

Annual organisms- an organism that has a one-year life span

Perennial organism- an organism that has a life span of more than one year

Senescence- A gradual descrease in fecundity and an increase in the probability of mortality.

LT 4: Life histories are sensitive to environmental conditions

Environmental stimuli for change

Photoperiod- the amount of light that occurs each day; this changes by season. A steady increase or decrease of day length can trigger life history events.

Ex: matting, migration, defending territories

Effects of food resources

Effects of prediation